This invention relates to the storing, handling, and injecting of radioactive materials and, more particularly, to an improved system for storing, handling, and injecting radioactive isotope-containing fluids.
For various types of diagnostic testing it is necessary to inject radioactive materials into a patient. It is well recognized that technicians who handle these materials need protection against the perils of cumulative ionizing radiation exposure, so provision is commonly made for shielding the materials until such time as they are injected into the patient. Toward this end, various types of syringe shields have been developed. The typical prior art syringe shield includes a lead cylinder which fits over a syringe, the lead body having a window of leaded glass which allows the operator to see the scale on the syringe which is placed within the lead cylinder.
There are a number of disadvantages associated with commercially available syringe shield designs. Some units have a simple cylindrical casing which does not provide adequate shielding forwardly or rearwardly of the syringe length. A further problem is that there is no standardization of syringe sizes, and even syringes having the same volume often have different physical dimensions. For example, a 10 cc syringe may have various possible diameters depending on the particular manufacturer. Thus, special provision is generally necessary to fit a syringe shield to the different possible syringe sizes. For example, in one prior art design the syringe shield is provided with a "set screw" which adjustably protrudes into the syringe shield's bore and engages the syringe so that it cannot move around within the syringe shield. The use of this technique involves some inconvenience and can occasionally cause breakage of the syringe.
In addition to the difficulties encountered in the prior art due to the necessity for providing shielding for syringes which are used to inject materials emitting ionizing radiation, there are a number of distinct problems associated with the overall handling and storage of the radioactive materials. The procedure followed by a clinical facility utilizing injectable radioactive materials is generally as follows: a specified gross amount of material is ordered from a supplier in heavy shielded containers, these containers sometimes being in the form of a "generator" in which specified isotopes are converted to the form in which they are to be ultimately injected into a patient. Since the gross supply of material continuously loses potency, it has a limited life and material not utilized within a prescribed time loses its value. Accordingly, and since supplies are generally provided in relatively large containers, it is important to have a good estimate of the intended material requirements before ordering the supply for a given time period. However, since the number of patients to be tested during a given period is the subject of fortuitous circumstance, improper estimation and waste often result. When a patient is to be injected with a radioactive isotope, a technician will typically insert a syringe into a syringe shield and then transfer material from the supply case into the shielded syringe. Although shielding is utilized, this loading operation involves a risk of exposure. A further risk of exposure is involved if the technician requires an assay of the radioactive material now in the syringe, since the shielding is typically removed to perform this operation. Next, the radioactive material is injected into the patient, and the syringe shield is removed (and saved for the next usage) while the syringe is either disposed of or cleaned for subsequent usage. These operations involve some risk of residual contamination remaining on the shield or reusable syringe. Also, the overall above-described procedure involves substantial inconvenience of transferring materials, applying and removing shielding, and cleaning.
In the abovereferenced copending application Ser. No. 668,531, now U.S. Pat. No. 4,056,096, there is disclosed a shielded syringe suitable for partial disposability. It is an object of the present invention to further overcome the problems of the prior art as set forth and to provide a convenient system for transporting, storing and injecting radioactive isotope-containing fluids which minimizes risks of exposure, allows economies of ordering, is convenient to use, and is relatively inexpensive.